Cilia beat with two distinctive phases.With the stroke,they stroke like an oar,thereby propelling the organism through the water.With the stroke,cilia bend along their length while they are pulled forward.

Question

Cilia beat with two distinctive phases.With the __________ stroke,they stroke like an oar,thereby propelling the organism through the water.With the __________ stroke,cilia bend along their length while they are pulled forward.